Exception:

Labels should have a section and a name

Resolution:

This exception is thrown when the custom label import in the Salesforce Lightning Web Component declaration is incorrect.

Sample Lightning Web Component:

HTML:

<template>
    <lightning-card>
        {sampleLabel}
    </lightning-card>
</template>

JavaScript:

import { LightningElement } from 'lwc';
import Sample_Label from "@salesforce/label/c.Sample_Label";

export default class SampleLightningWebComponent extends LightningElement {

    sampleLabel = Sample_Label;
    
}

js-meta.xml:

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>62.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightning__Tab</target>
    </targets>
</LightningComponentBundle>

I faced this exception when I missed the c namespace. So, use c.Sample_Label instead of just Sample_Label.